The present invention relates generally to the transmission, broadcasting, and/or storage of information and/or data. More particularly, the present invention relates to forward error correction of the data to be transmitted, broadcasted, and/or stored. Some embodiments according to the present invention relate to a forward error correction data generator. Some embodiments of the present invention relate to a forward error correction decoder. Some embodiments relate to a method for generating forward error correction data. Further embodiments relate to a method for forward error correction decoding. Some aspects of the present invention relate to the reconstruction of FEC (forward error correction) source blocks with synchronization SI (symbol ID).
Video coding techniques are nowadays still investigated in order to support, for example, increasing spatial resolutions (e.g. UHD, ultra high definition). Other research interest are the reduction of data to be transmitted and/or an optimization of the coding efficiency, in particular for mobile applications. Among the available video coding standards, H.264/MPEG-4 AVC standard is probably the most widely used with more than 1 billion devices.
Since the introduction of the H.264/MPEG-4 AVC standard in 2003, several extension to the base standard have been successfully launched, for example the Scalable Video Coding amendment (SVC) and the Multiview Video Coding amendment (MVC) of the H.264/AVC standard.
The Scalable Video Coding amendment (SVC) of the H.264/AVC standard provides network-friendly scalability at a bit stream level with a moderate increase in decoder complexity relative to single-layer H.264/AVC. It supports functionalities such as bit rate, format, and power adaptation, graceful degradation in lossy transmission environments as well as lossless rewriting of quality-scalable SVC bit streams to single-layer H.264/AVC bit streams. These functionalities provide enhancements to transmission and storage applications. SVC has achieved significant improvements in coding efficiency with an increased degree of supported scalability relative to the scalable profiles of prior video coding standards.
The Multiview Video Coding amendment (MVC) of the H.264/AVC standard provides view scalability at the bitstream level. This allows the efficient transmission of multiview video (e.g., video with 2 views suitable for viewing on a stereo display) in an efficient and backward compatible way. A legacy H.264/AVC decoder decodes only one (the so-called base view) of the two views that are included in the multiview bitstream. The reconstructed video sequence can be displayed on a conventional 2d display. On the contrary, a stereo decoder is capable of decoding both views and the decoded video sequences (one for the left and one for the right eye) are suitable for 3d displays.
Both SVC and MVC can be considered as examples of so called layered media coding technologies which generate video bit-streams with various media layers, each of them representing another level of quality. Due to inter-layer prediction there exist hierarchies between these media layers, where media layers depend on other media layers for successful decoding. Layer-Aware Forward Error Correction (LA-FEC) exploits the knowledge of the existing dependency structures within layered media streams. LA-FEC generates FEC data so that protection of less important media layers can be used with protection data of more important media layers for joint error correction. In this way, LA-FEC enables new functionalities and increases the protection of more important media without increasing the total amount of data.
In order to correct errors in received data at a receiver side of a transmission channel by employing Layer-Aware Forward Error Correction, a FEC decoder necessitates knowledge about the correspondence between a given portion of payload data and the portion of FEC parity data that can be used for correcting errors (e.g., transmission errors) in said portion of payload data. In other words, the FEC decoder has to be able to establish a link between the portion of payload data and the corresponding portion of FEC parity data, in order to successfully correct errors in the payload data and/or the FEC parity data. This aspect becomes in particular important when the base representation, the enhancement representation, and the FEC parity information are transmitted using different data flows or streams. Another possibly scenario in which the correspondences between payload data and FEC parity data might not be straight forward is when the payload data and the FEC parity data are transmitted via packet-switched network so that each packet can take different routes and arrive at different times at the receiver.
Efficient and/or robust signaling of correspondence between FEC parity data and payload data is therefore desirable for improving error correction capabilities and/or error correction efficiency, among others.